scholarly journals A Statistical Analysis of Observational Hubble Parameter Data to Discuss the Cosmology of Holographic Chaplygin Gas

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 701
Author(s):  
Amrita Sarkar ◽  
Surajit Chattopadhyay ◽  
Ertan Güdekli
Keyword(s):  
Equation Of State ◽  
Hubble Parameter ◽  
Polynomial Regression ◽  
Chaplygin Gas ◽  
Ricci Dark Energy ◽  
Chi Square ◽  
Generalized Chaplygin Gas ◽  
Eos Parameter ◽  
Order Polynomial ◽  
Chi Square Test

A scheme for the generalized Chaplygin gas equation of state is shown by using the holographic Ricci dark energy. Regression analysis and a chi-square test were performed. A second order polynomial regression has been established as the relation between the Hubble Parameter and redshift. It has established a set of parameters that can predict the Equation of State (EoS) parameter.

VISCOUS GENERALIZED CHAPLYGIN GAS

2006 ◽  
Vol 15 (08) ◽  
pp. 1151-1161 ◽  
Author(s):  
XIANG-HUA ZHAI ◽  
YOU-DONG XU ◽  
XIN-ZHOU LI
Keyword(s):  
Equation Of State ◽  
Bulk Viscosity ◽  
Critical Energy ◽  
State Equation ◽  
Chaplygin Gas ◽  
Point Of View ◽  
Dynamical Analysis ◽  
Density Parameter ◽  
Generalized Chaplygin Gas ◽  
Barotropic Fluid

Viscous generalized Chaplygin gas (GCG) cosmology is discussed, assuming that there is bulk viscosity in the linear barotropic fluid and GCG. wγ = γ - 1 and wg represent the state equation parameters for barotropic fluid and GCG, respectively, in which γ = 1 or [Formula: see text] corresponds to ordinary matter or radiation. The dynamical analysis indicates that the phase [Formula: see text] is a dynamical attractor and the equation of state of GCG approaches it from either wg > -1 or wg < -1 depending on the choice of its initial cosmic density parameter and the ratio of pressure to critical energy density, where τg and τγ are viscosity parameters. Therefore, the equation of state wg will cross the boundary wg = -1 if we choose initial value wg < -1. Furthermore, we show that bulk viscosity coefficients should satisfy inequalities from the point of view of dynamics.

scholarly journals GEOMETRICAL DIAGNOSTIC FOR THE GENERALIZED CHAPLYGIN GAS MODEL

2009 ◽  
Vol 18 (11) ◽  
pp. 1741-1748 ◽  
Author(s):  
JIANBO LU ◽  
LIXIN XU
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Equation Of State ◽  
Diagnostic Method ◽  
Chaplygin Gas ◽  
Shift Parameter ◽  
Generalized Chaplygin Gas ◽  
Λcdm Model ◽  
Current Equation

A new diagnostic method, Om, is applied to the generalized Chaplygin gas (GCG) model as the unification of dark matter and dark energy. On the basis of the recently observed data — the Union supernovae, the observational Hubble data, the SDSS baryon acoustic peak and the five-year WMAP shift parameter — we show the discriminations between the GCG model and the ΛCDM model. Furthermore, it is calculated that the current equation of state of dark energy w 0de = -0.964, according to the GCG model.

Stability of a charged rotating BTZ thin shell with a different variable equation of state

2021 ◽  
pp. 2150086
Author(s):  
A. Eid
Keyword(s):  
Black Holes ◽  
Equation Of State ◽  
Thin Shell ◽  
Mechanical Stability ◽  
Chaplygin Gas ◽  
Throat Radius ◽  
Generalized Chaplygin Gas ◽  
Radial Perturbation ◽  
Btz Black Holes ◽  
Variable Equation

Dynamics of charged rotating BTZ black holes in 2 + 1 dimensions by using the cut and paste approach is discussed. Due to the mechanical stability of rotating charged BTZ thin shell, the radial perturbation about the equilibrium throat radius and three variable equation of state (EoS) is analyzed. Several examples are displayed satisfying it, such as variable Phantom-like, variable Chaplygin gas and variable modified generalized Chaplygin gas.

scholarly journals Spherical "Top-Hat" collapse in a modified Chaplygin gas dominated universe

2015 ◽  
Vol 24 (07) ◽  
pp. 1550050 ◽  
Author(s):  
S. Karbasi ◽  
H. Razmi
Keyword(s):  
Equation Of State ◽  
Structure Formation ◽  
Observational Data ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
Time Rate ◽  
Generalized Chaplygin Gas ◽  
The Stability ◽  
Perturbation Growth ◽  
Good Agreement

Considering perturbation growth in spherical Top-Hat (STH) model of structure formation in a generalized Chaplygin gas (GCG) dominated universe, we want to study this scenario with modified Chaplygin gas (MCG) obeying an equation of state p = A - B/ρα model. Different parameters of this scenario for positive and negative values of A are computed. The evolution of background and collapsed region parameters are found for different cases. The stability of the model and the collapse time rate are considered in different cases. The turn-around redshifts for different values of α are computed; the results are in relatively good agreement with current observational data.

scholarly journals STATEFINDER DIAGNOSTIC FOR DARK ENERGY MODELS IN BIANCHI I UNIVERSE

2012 ◽  
Vol 21 (05) ◽  
pp. 1250046 ◽  
Author(s):  
M. SHARIF ◽  
RABIA SALEEM
Keyword(s):  
Dark Energy ◽  
Holographic Dark Energy ◽  
Chaplygin Gas ◽  
Accelerated Expansion ◽  
Ricci Dark Energy ◽  
Generalized Chaplygin Gas ◽  
Bianchi I ◽  
Energy Models ◽  
Expansion Of The Universe ◽  
The Universe

In this paper, we investigate the statefinder, the deceleration and equation of state parameters when universe is composed of generalized holographic dark energy or generalized Ricci dark energy for Bianchi I universe model. These parameters are found for both interacting as well as noninteracting scenarios of generalized holographic or generalized Ricci dark energy with dark matter and generalized Chaplygin gas. We explore these parameters graphically for different situations. It is concluded that these models represent accelerated expansion of the universe.

scholarly journals Statefinder and Om Diagnostics for New Generalized Chaplygin Gas Model

Universe ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 362
Author(s):  
Abdulla Al Mamon ◽  
Vipin Chandra Dubey ◽  
Kazuharu Bamba
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Observational Data ◽  
Hubble Parameter ◽  
Chaplygin Gas ◽  
Distance Modulus ◽  
Generalized Chaplygin Gas ◽  
New Model ◽  
Λcdm Model ◽  
Data Points

We explore a unified model of dark matter and dark energy. This new model is a generalization of the generalized Chaplygin gas model and is known as a new generalized Chaplygin gas (NGCG) model. We study the evolutions of the Hubble parameter and the distance modulus for the model under consideration and the standard ΛCDM model and compare that with the observational datasets. Furthermore, we demonstrate two geometric diagnostics analyses including the statefinder (r,s) and Om(z) to the discriminant NGCG model from the standard ΛCDM model. The trajectories of evolution for (r,s) and Om(z) diagnostic planes are shown to understand the geometrical behavior of the NGCG model by using different observational data points.

scholarly journals A study of modified holographic Ricci dark energy in the framework of f(T) modified gravity and its statefinder hierarchy

2019 ◽  
Vol 97 (5) ◽  
pp. 477-486 ◽  
Author(s):  
Arkaprabha Majumdar ◽  
Surajit Chattopadhyay
Keyword(s):  
Dark Matter ◽  
Fixed Point ◽  
Dark Energy ◽  
Modified Gravity ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
Ricci Dark Energy ◽  
Eos Parameter ◽  
The Universe ◽  
Viable Model

Inspired by the work of Bamba et al. (Phys. Rev. D, 85, 104036 (2012)) the present paper reports a study on the reconstruction of modified holographic Ricci dark energy (MHRDE) in the framework of modified gravity taken as f(T) gravity. A correspondence between modified Chaplygin gas and MHRDE has also been considered and thereinafter the f(T) gravity has been reconstructed via reconstruction of the Hubble parameter. The reconstructed equation of state (EoS) parameter obtained this way has been found to be able to cross the phantom boundary. In the next phase of the work, a viable model of f(T) gravity has been considered and MHRDE has been discussed in this modified gravity frame. The EoS parameter due to the torsion contribution obtained this way has been found to behave like quintessence. The transition of the universe from the dark matter dominated to dark energy (DE) dominated phase is apparent from this model. Also, the model is exhibiting DE domination of the current universe. Finally, the statefinder hierarchy has been discussed through the statefinder and snap parameters. The model has been found to be able to attain the ΛCDM fixed point in the statefinder trajectory.

THE EVOLUTION OF GENERALIZED CHAPLYGIN GAS

2006 ◽  
Vol 21 (15) ◽  
pp. 1233-1239 ◽  
Author(s):  
YABO WU ◽  
XUEMEI DENG ◽  
JIANBO LU ◽  
SONG LI ◽  
XIUYI YANG
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Equation Of State ◽  
Deceleration Parameter ◽  
Critical Density ◽  
Chaplygin Gas ◽  
Generalized Chaplygin Gas ◽  
Big Rip ◽  
The Future ◽  
The Universe

We consider the generalized Chaplygin gas (GCG) proposal for the unification of dark matter and dark energy with p = pdeand ρ = ρdm+ρde. The unified equation of state for GCG has been obtained: [Formula: see text]. On the basis of the function χ(z), some cosmological quantities such as the fractional contributions of different components of the universe Ωi(i respectively denotes baryons, dark matter and dark energy) to the critical density, the equation of state for dark energy ωde, the deceleration parameter q are all obtained, which are consistent with observations. In addition, the transition from deceleration to acceleration is described in our model. We find that the behavior of GCG will be like ΛCDM in the future. So, it has been ruled out in our model that our universe will end up with Big Rip in the future.

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